The present invention relates to the controlled editing and broadcasting of any audiovisual and multimedia file and content, by and to authorized users and provides a method and a system for the controlled editing and broadcasting of audiovisual and multimedia files and contents.
The general issue is to provide a device able to controllably diffuse compressed digital audiovisual and multimedia files of the MPEG type for video, JPEG type for still images or MP3 type for audio, to authorized users, and to enable them to edit said files by creating new audiovisual and multimedia files from one or several extracts of one or several independent audiovisual and multimedia files. With the present solutions, it is possible to transmit multimedia contents in a digital form via any network type. To avoid the hacking of thus diffused fluxes, said contents are often encrypted by various means which are well known to the persons skilled in the art.
However, the main drawback of the current solutions consists in that it is necessary to transmit not only the encrypted contents to the users, but also the decryption keys or the utilization licenses to the user terminal, so as to enable the execution of said contents. If the utilization licenses did not take into account the fact of being able to extract a predefined part of a content to edit it or to combine it with another predefined extract of the same, or of another content, after the encryption of the contents, this functionality cannot generally be performed. Thus, the present real time broadcasting solutions (streaming) or downloading solutions have major drawbacks such as the impossibility of editing said contents if they are protected by extremely efficient licenses or, on the contrary, they provide a malevolent user the possibility of making non authorized copies of the thus diffused contents if the encryption methods are not sufficient enough. Another drawback of the downloading is that it requires the complete downloading of the file even though a user wishes to see only one extract thereof, or start at another moment than the beginning of the file.
Under these conditions, a solution consists in separating the parent digital file into two parts, none of which could be used alone. With this idea in mind, several patents have been filed. Thus, it is known from document WO 01/69354 A3 (Microsoft Corporation) which discloses a system protecting a digital product (software or audio or video content using an encryption, by breaking it down into at least two portions. Both portions are encrypted after the separation and wholly and integrally transmitted to the user equipment through separate ways. The recombination of both parts on the receiving equipment is carried out using keys, which recreate a modified digital product which is substantially equivalent to the original product and which is appropriate only for this user equipment. This system recombines both parts to create a new digital product and thus cannot guarantee that said new digital product cannot be edited to make an extract thereof since the whole digital product is recreated by a given machine. This system does not allow the assembling of extracts either.
In the state of the art solutions are also known, making it possible to edit an audio file by dividing it into at least two segments and by retrieving therefrom one or several segments of the file. The application of patent WO 00/49597 was filed with this idea in mind and provides a method for encrypting data characterised in that it provides a set of sounds, retrieves one or several segments from the set to make a specific file, provides a decryption key, encrypts the specific file and communicates said encrypted specific file on a first communication channel and the retrieved segments on a second communication channel. The drawback of such a solution lies in the impossibility to control the utilization of the transmitted specific file. The lawful or fraudulent holder or the decryption key can use the file unconditionally and permanently. The issue of controlling the free flow of multimedia files on a network is not solved yet.
In order to remedy these various defects, the invention provides to enable the holder of rights to freely diffuse and to put on line his or her audiovisual and multimedia contents with maximum comfort and reading quality for the user of a terminal, independently from the rate of his or her connection to the telecommunication network. The invention also aims at enabling a user to read some extracts, to edit said extracts and to assemble them into a new audiovisual and multimedia file which can be broadcast within the limits of the holder's rights.
For this purpose, the invention relates to a method for editing and broadcasting compressed multimedia files composed of binary data blocks originating from digital transformations applied to an audiovisual or multimedia content according to a format of a parent file, said parent file having been divided into a first modified file having the format of the nominal parent file, and into a complementary file including information on the modifications brought to said parent file, characterised in that it includes, prior to the transmission from a portal to a receiving terminal:                a step of preparation consisting in analyzing said first file to extract time-codes therefrom,        a second step consisting in generating an index register table from said first modified file,        a third step consisting in generating a modified multimedia file according to the format of the parent file containing information on said first modified file and meta-data,        a step of transmission:        of said modified multimedia file, and        by means separate from said multimedia file, the elements from said complementary file making it possible to recreate a partial synthesis of the original audiovisual file, from the calculations on the receiving terminal, as a function of said modified multimedia file and the elements of said complementary file.        
Advantageously, the referencing of said complementary file is generated during said second step. Advantageously, said meta-data of said third step contain said time-codes from said step of preparation. Advantageously, said meta-data of said third step containing said referencing of said complementary file. Advantageously, said meta-data from said third step contain said index register table.
In a particular embodiment, the whole or a part of said modified multimedia file is sent by a portal. Advantageously, the whole or a part of said modified multimedia file is sent by another terminal. Advantageously, the whole or a part of said modified multimedia file is sent by a physical medium.
In another embodiment, said portal decides which elements of said complementary file are to be sent to said receiving terminal, as a function of the characteristics of said terminal. Advantageously, said portal decides which elements from said complementary file are to be sent to said receiving terminal, as a function of the utilization conditions imparted by the holder of the rights on said parent file. In a particular embodiment, said partial synthesis of the recreated content is executed upon reception of the first information of said modified multimedia file 34 and the first elements from said complementary file 33. In another embodiment, said modified multimedia file is edited to create an extract of said modified multimedia file.
Advantageously, several extracts of modified multimedia files are assembled to create a new modified multimedia file. Advantageously, said extracts of modified multimedia files originate from only one modified multimedia file. Advantageously, said extracts of modified multimedia files originate from several modified multimedia files.
Eventually, the invention relates to a system for the transmission of a compressed audiovisual file for the implementation of the method, characterised in that it includes equipment for producing one modified multimedia file, at least equipment for operating an audiovisual flow between the production equipment and the operating equipment. Thus, the invention enables a total control of the utilization of copies and the conditions of utilization thereof, these conditions being imparted by the holder of rights on the parent content, of new files and audiovisual and multimedia contents thus broadcast or edited.